In recent years, LED-based lighting solutions have been developed. These are able to provide additional features, above and beyond those of traditional lighting (e.g. incandescent, CFL) technologies. These include, among others, the possibility of tuning the color temperature (e.g. from warm white to cool white) and/or creating a large gamut of colors. For example, the Philips Hue family of products allow for both options: temperature tuning from 2200K to 6500K and around 16 million possible color combinations.
One of the main drivers for this development is allowing customers to go beyond the common use of lighting (either fixed brightness or dimmable brightness) and use these lamps for what is known as mood setting: adapt the lighting in a specific room to match certain decoration, use color combinations to highlight areas and hide others, increase the feeling of warmth or induce higher concentration or energy in users etc.
A lighting system for illuminating an environment typically comprises one or more luminaires, each of which, in turn, comprises one or more lamps such as LED lamps that emit configurable illumination into the environment. Where a luminaire comprises multiple lamps, these may, in some cases, be independently controllable at least to some extent. In order to control the lamps across the luminaire(s), they are connected (e.g. wirelessly or by wired means) to a control mechanism, such as a bridge (e.g. lighting bridge, or home automation server), and thus form a lighting network in which network nodes are e.g. lamps or sets of lamps and/or luminaires or sets of luminaires. The network may have a star topology, whereby the bridge communicates with all nodes directly, a mesh topology, whereby nodes relay control signals to/from the bridge from/to other nodes, or any other suitable network topology e.g. based on a combination of star and mesh-like connections. The network may comprise other types of node, such as dedicated controllers, routers, switches etc.
Mood setting is a key element in modern lighting systems and can be achieved by means of lighting “scenes”. Each scene is defined by a respective set of configuration data (scene data set) for a group lamps that belong to that scene, i.e. to which that scene data set relates. The lamp(s) may be of one luminaire or spread across multiple luminaires. The scene data set contains information on which lamps belong to it and defines one or more illumination settings for those lamps. E.g. color setting(s) and/or brightness setting(s), such as a color point and/or a brightness at which each of the lamps is set. Settings in a scene data set may be global (applying to all lamps in the group), individual (applying to only a single lamp in the group), or somewhere in between (applying to a subset of lamps). Users can have multiple scenes configured for each of the possible moods they want to represent (or other ambiance-creating scenarios), and select between them as desired.
From a technological point of view this is enabled not only by the lighting capabilities of the lamps but also by a smart system that can control them according to inputs from users and which communicates internally using a wired (e.g. DMX, DALI) or wireless (e.g. ZigBee) mechanism. Due to this a user can transfer, with minimum effort, the desired configuration or scene recall to all the involved elements. This is referred to in the art as “connected lighting”.
A problem in connected lighting is that the devices that belong to a lighting network, and which thus might be part of scenes, can become unreachable. This can occur, for example, if they are out of range, they are not powered, or due to an internal malfunction they cannot communicate or act upon those commands
A device that is out of range cannot be communicated with, and as a result it will not change its last state based on inputs from the user. This can for example be caused by:
Some temporary effect that alters the range between critical nodes in a wireless system. For example, increased momentary traffic in the network or some object being placed between devices that does not allow RF signals to propagate correctly;
A device (e.g. a portable lamp) being moved from its last location and it's last location is not suitable for RF communication or is too far away from the closest device;
A node in the network which is key in relying messages to a subgroup of nodes is unreachable, and though there is no specific issue with the subgroup itself, the unreachability of the key node splits the network in two disconnected sections.
In the case of a device that is not powered, this can be because it has been removed/destroyed, the power connection that it requires has been removed (e.g. a wall switch is flipped off for a wireless lamp), or its internal battery source has been depleted (for a battery powered lamp).
In some cases a lamp could seem unreachable even though it is in range and powered; this could be due to an internal malfunction in the device that momentarily or permanently disables the device's capability to communicate and, as such, cannot change its lighting setting. For example, a lamp which has had its internal software updated with an error (i.e. “bug”), could from a wireless point of view still be in range, could be powered by either mains or battery, but could be in an endless loop of software reset from which it cannot get out and as such it ignores all incoming commands from the network
Some existing types of bridge include a mechanism to retrieve the availability status of the known nodes, and are thus able to inform the user about the unreachability of the device.
WO 2009/060369 A2 relates to the automatic rendering of a lighting scene with a lighting system, particularly the control of the rendering. A basic idea of the invention is to improve rendering of a lighting scene by automatically compensating interference, such as an alien light source or a dynamic perturbing even of a rendered lighting scene. An embodiment of the invention provides a light control system for automatically rendering a lighting scene with a lighting system, wherein the light control system is adapted for monitoring the rendered lighting scene for the occurrence of interference, and automatically reconfiguring the lighting system such that a monitored occurrence of an interference is compensated. As result, the invention allows to prevent dynamic disturbances or unforeseen events, for example caused by faulty or alien light sources, from distorting the rendering of an intended lighting scene.
US 2012/0068608 A1 relates to a system for auto-commissioning a light fixture which may position the light fixture based on sensor data received from at least one sensor. In order to focus the light fixture on a target location, the system may vary the position of the light fixture and determine a position of the light fixture where the light level received by the photosensor reaches a determined light level. The system may adjust a light characteristic of light emitted by the light fixture so that the color of light received by the photosensor at the target location matches a target light characteristic, such as color or intensity. The system may determine a focus position and a light characteristic for multiple target locations. The system may auto-commission multiple light fixtures.